The coatings and printing ink industries have been around for centuries and, as such, have developed a variety of methods to characterize their products. Many of these methods have been codified in ASTM Method D 5010-03, Standard Guide for Testing Printing Ink and Related Materials.1 This is an exhaustive list of over 100 tests that are used to characterize ink-related materials. (ASTM volumes D 6.01 – 6.04 are related to coatings.) While this compilation contains many types of methods, some of the most common ones revolve around particle size determination. These tests can be characterized as either direct or indirect procedures, with both types addressing the same issues. Direct methods actually determine particle size, while indirect methods measure performance that is determined by particle size.
Particle size measurement is a collection of very old and very modern analytical techniques. It originated thousands of years ago with sieving as a method of characterizing the efficiency of crushing operations. Since this beginning, many methods of making this determination have evolved.During this evolution, the test procedures have become quicker, easier and more repeatable.